A novel phenylpropenoyl sulfonic acid and a new chlorophyll from the leaves of Petasites formosanus KITAMURA.

A novel phenylpropenoyl sulfonic acid, petasiformin-A (1), and a new chlorophyll, petasiphyll-A (2), were isolated from the leaves of Petasites formosanus KITAMURA (Compositae). Their structures were established by spectral and chemical transformation methods. Petasiformin-A (1) showed the significant antioxidative activity in DPPH radical scavenging assay.